Process for producing hydroxylamine

ABSTRACT

It is an object of the present invention to provide a process for producing a hydroxylamine by reacting a salt of hydroxylamine with an alkali compound, where the yield reduction due to formation of a complex between the produced hydroxylamine and a salt produced as a by-product or adsorption of the hydroxylamine to the by-product salt is decreased, and a high-concentration and high-purity hydroxylamine is safely produced at a high yield. 
     The process for producing a hydroxylamine of the present invention comprises a reaction step of reacting a salt of hydroxylamine with an alkali compound to obtain a hydroxylamine while keeping the reaction solution at a pH of 7 or more, a purification step of purifying the hydroxylamine by ion exchange, and a concentration step of concentrating the hydroxylamine by distillation at the column bottom.

CROSS REFERENCES OF RELATED APPLICATION

This application is the national stage application under 35 U.S.C. §371of PCT/JP2004/011854 filed Aug. 12, 2004 claiming benefit pursuant to 35U.S.C. §119(e) of the filing dates of Provisional Application No.60/496,666 filed on Aug. 21, 2003 and 60/541,070 filed on Feb. 3, 2004pursuant to 35 U.S.C. §111(b).

TECHNICAL FIELD

The present invention relates to a process for producing a hydroxylamineby reacting a salt of hydroxylamine with an alkali compound, where ahigh-concentration and high-purity hydroxylamine is safely produced at ahigh yield.

BACKGROUND ART

Hydroxylamines and salts thereof are being used in industry over a widerange of uses such as raw material of intermediate for medicines oragrochemicals, surface-treating agent for metal, fiber treatment ordyeing. Free hydroxylamines have a very unstable property, for example,these readily undergo decomposition in the presence of metal ion(particularly, heavy metal ion) under the high-temperature orhigh-concentration condition. Accordingly, in general, a salt ofhydroxylamine, which is relatively stable, is produced and used.

However, in many uses, a hydroxylamine is more preferred than a salt ofhydroxylamine and also, an aqueous hydroxylamine solution in a highconcentration is often required. Furthermore, for use in electronicindustry, a high-purity hydroxylamine having less metal impurities isrequired. In order to meet these requirements, attempts are being madeto suppress the decomposition reaction and efficiently and safelyproduce a high-concentration aqueous hydroxylamine solution.

For example, German Patent Publication No. 3,528,463 (Patent Document 1)discloses a process of adding an oxide and/or a hydroxide of calcium,strontium or barium to an aqueous hydroxylamine sulfate solution havinga small ammonium ion content, performing the reaction at a temperatureof 20° C. or less and removing by separation the insoluble sulfate.

JP-A-2002-12415 (Patent Document 2) discloses a process of producing ahydroxylamine by adding a slurry of calcium oxide and/or calciumhydroxide to an aqueous solution containing hydroxylamine sulfate,thereby performing the reaction, where the reaction is performed in thestate that calcium sulfate as the seed slurry is always present in thereaction system, as a result, the particle size of insoluble sulfate isincreased to enhance the filtration efficiency and a hydroxylamine isefficiently produced.

However, these conventional processes of adding an alkali compound to anaqueous solution containing hydroxylamine sulfate have a problem thatthe produced hydroxylamine forms a complex with a sulfate produced as aby-product or adsorbs to the sulfate and the yield of hydroxylaminedecreases.

Also, JP-A-2000-510385 (Patent Document 3) describes a process ofseparating an aqueous solution containing a hydroxylamine and a saltinto an aqueous hydroxylamine solution and a salt fraction by stripping.

JP-A-2001-513479 (Patent Document 4) describes a process of treating asalt of hydroxylamine with a base and separating the produced solutioninto an aqueous hydroxylamine solution and a salt fraction.

JP-A-2002-504062 (Patent Document 5) describes a process ofconcentrating an aqueous hydroxylamine solution by distillation,removing the hydroxylamine-containing vapor from the side face at thecolumn bottom, and concentrating the vapor.

U.S. Pat. No. 6,235,162 (Patent Document 6) describes a process ofobtaining a hydroxylamine by extracting a hydroxylamine from the columntop by distillation and further distilling the obtained distillate.

JP-A-2002-68718 (Patent Document 7) describes a process of distillingout a hydroxylamine from the column top by simply distilling an aqueoushydroxylamine solution.

However, these processes have a problem that at the time of obtaining ahydroxylamine from the column top or side by distillation, thehydroxylamine may undergo decomposition or explosion due to distillationat a high temperature.

[Patent Document 1] German Patent Publication No. 3,528,463 [PatentDocument 2] JP-A-2002-12415 [Patent Document 3] JP-A-2000-510385 [PatentDocument 4] JP-A-2001-513479 [Patent Document 5] JP-A-2002-504062[Patent Document 6] U.S. Pat. No. 6,235,162 [Patent Document 7]JP-A-2002-68718

DISCLOSURE OF INVENTION

An object of the present invention is to provide a process for producinga hydroxylamine by reacting a salt of hydroxylamine with an alkalicompound, where the yield reduction due to formation of a complexbetween the produced hydroxylamine and a salt produced as a by-productor adsorption of the hydroxylamine to the by-product salt is suppressedand a high-concentration hydroxylamine is produced at a high yield.

Also, an object of the present invention is to provide a process forproducing a hydroxylamine by reacting a salt of hydroxylamine with analkali compound, where a high-concentration and high-purityhydroxylamine is safely produced at a high yield.

As a result of intensive investigations to solve those problems, thepresent inventors have found that a hydroxylamine can be produced at ahigh yield when the reaction is performed by adding a salt ofhydroxylamine to a reaction solution containing an alkali compound, andalso that a hydroxylamine can be produced at a high yield by performingthe reaction while keeping a reaction solution containing a salt ofhydroxylamine and an alkali compound at a pH of 7 or more.

Also, the present inventors have found that a high-concentration andhigh-purity hydroxylamine can be safely produced at a high yield bycombining, for example, a reaction step of reacting a salt ofhydroxylamine with an alkali compound to obtain a hydroxylamine, aseparation step, if desired, of separating by solid-liquid separationinsoluble substances precipitated in the reaction solution from thehydroxylamine obtained in the reaction step, a purification step ofpurifying by ion exchange the hydroxylamine obtained in the separationstep, and a concentration step of concentrating the hydroxylamineobtained in the purification step, by distillation at the column bottom.

According to the knowledge of the present inventors, when the productionprocess of the present invention is used, the produced hydroxylaminedoes not form a complex with a salt produced as a by-product and theamount of hydroxylamine adsorbed to the by-product salt is small, sothat a high-concentration and high-purity hydroxylamine can be safelyobtained at a high yield. This knowledge has been found out for thefirst time by the present inventors.

The present invention has been made based on this knowledge and relatesto (1) to (39) below.

(1) A process for producing a hydroxylamine by reacting a salt ofhydroxylamine with an alkali compound, comprising a reaction step ofreacting a salt of hydroxylamine with an alkali compound while keepingthe reaction solution at a pH of 7 or more.

(2) A process for producing a hydroxylamine by reacting a salt ofhydroxylamine with an alkali compound, comprising a reaction step ofperforming the reaction by adding a salt of hydroxylamine to a reactionsolution containing an alkali compound.

(3) The process for producing a hydroxylamine as described in (2),wherein the reaction step is performed while keeping the reactionsolution at a pH of 7 or more.

(4) The process for producing a hydroxylamine as described in any one of(1) to (3), wherein the alkali compound is at least one compoundselected from the group consisting of an alkali metal compound, analkaline earth metal compound, an ammonia and an amine.

(5) The process for producing a hydroxylamine as described in any one of(1) to (4), wherein the salt of hydroxylamine is at least one saltselected from the group consisting of hydroxylamine sulfate,hydroxylamine hydrochloride, hydroxylamine nitrate and hydroxylaminephosphate.

(6) The process for producing a hydroxylamine as described in any one of(1) to (5), wherein the reaction temperature at the reaction step isfrom 0 to 80° C.

(7) The process for producing a hydroxylamine as described in any one of(1) to (6), wherein the reaction step is performed in the presence of asolvent containing water and/or an alcohol.

(8) The process for producing a hydroxylamine as described in any one of(1) to (7), wherein the reaction step is performed in the presence of astabilizer.

(9) The process for producing a hydroxylamine as described in any one of(1) to (8), which comprises a separation step of separating insolublesubstances from the hydroxylamine.

(10) The process for producing a hydroxylamine as described in (9),wherein the temperature at the separation step is from 0 to 80° C.

(11) The process for producing a hydroxylamine as described in (9) or(10), wherein at least a part of the reaction solution after separatinginsoluble substances in the separation step is used as a solvent fordissolving or suspending a salt of hydroxylamine and/or an alkalicompound which are reaction raw materials.

(12) The process for producing a hydroxylamine as described in any oneof (1) to (11), which comprises a purification step of purifying thehydroxylamine.

(13) The process for producing a hydroxylamine as described in (12),wherein the purification step is a step of purifying the hydroxylamineby at least one method selected from the group consisting ofdistillation, ion exchange, electrodialysis, membrane separation,adsorption and crystallization.

(14) The process for producing a hydroxylamine as described in (12) or(13), wherein at least a part of the hydroxylamine solution obtained inthe purification step is used as a solvent for dissolving or suspendinga salt of hydroxylamine and/or an alkali compound which are reaction rawmaterials.

(15) The process for producing a hydroxylamine as described in any oneof (1) to (14), which comprises a concentration step of concentratingthe hydroxylamine.

(16) The process for producing a hydroxylamine as described in (15),wherein the concentration step is a step of concentrating thehydroxylamine by distillation at the column bottom.

(17) The process for producing a hydroxylamine as described in (15) or(16), wherein the temperature at the concentration step is from 0 to 70°C.

(18) The process for producing a hydroxylamine as described in (15) to(17), wherein at least a part of the hydroxylamine solution obtained inthe concentration step is used as a solvent for dissolving or suspendinga salt of hydroxylamine and/or an alkali compound which are reaction rawmaterials.

(19) The process for producing a hydroxylamine as described in (15) to(18), which further comprises a purification step of purifying thehydroxylamine by ion exchange after the concentration step.

(20) A process for producing a hydroxylamine, comprising a reaction stepof reacting a salt of hydroxylamine with an alkali compound to obtain ahydroxylamine, a purification step of purifying the hydroxylamine by ionexchange, and a concentration step of concentrating the hydroxylamine bydistillation at the column bottom.

(21) The process for producing a hydroxylamine as described in (20),wherein the steps for producing a hydroxylamine are performed in theorder of a reaction step, a purification step and a concentration step.

(22) The process for producing a hydroxylamine as described in (20) or(21), wherein each of the steps is performed in the presence of astabilizer.

(23) The process for producing a hydroxylamine as described in (20),which comprises a separation step of separating insoluble substancesfrom the hydroxylamine.

(24) The process for producing a hydroxylamine as described in (23),wherein the temperature at the separation step is from 0 to 80° C.

(25) The process for producing a hydroxylamine as described in (23) or(24), wherein the steps for producing a hydroxylamine are performed inthe order of a reaction step, a separation step, a purification step anda concentration step.

(26) The process for producing a hydroxylamine as described in any oneof (23) to (25), wherein each of the steps is performed in the presenceof a stabilizer.

(27) The process for producing a hydroxylamine as described in any oneof (23) to (26), wherein at least a part of the reaction solution afterseparating insoluble substances in the separation step is used as asolvent for dissolving or suspending a salt of hydroxylamine and/or analkali compound which are reaction raw materials.

(28) The process for producing a hydroxylamine as described in any oneof (20) to (27), wherein the reaction step is performed while keepingthe reaction solution at a pH of 7 or more.

(29) The process for producing a hydroxylamine as described in (28),wherein the reaction step is a step of adding a salt of hydroxylamine toa reaction solution containing an alkali compound.

(30) The process for producing a hydroxylamine as described in any oneof (20) to (29), wherein the reaction temperature at the reaction stepis from 0 to 80° C.

(31) The process for producing a hydroxylamine as described in any oneof (20) to (30), wherein the reaction step is performed in the presenceof a solvent containing water and/or an alcohol.

(32) The process for producing a hydroxylamine as described in any oneof (20) to (31), wherein the temperature at the purification step isfrom 0 to 70° C.

(33) The process for producing a hydroxylamine as described in any oneof (20) to (32), wherein at least a part of the hydroxylamine solutionobtained in the purification step is used as a solvent for dissolving orsuspending a salt of hydroxylamine and/or an alkali compound which arereaction raw materials.

(34) The process for producing a hydroxylamine as described in (20) to(33), wherein the temperature at the concentration step is from 0 to 70°C.

(35) The process for producing a hydroxylamine as described in any oneof (20) to (34), wherein at least a part of the hydroxylamine solutionobtained in the concentration step is used as a solvent for dissolvingor suspending a salt of hydroxylamine and/or an alkali compound whichare reaction raw materials.

(36) The process for producing a hydroxylamine as described in any oneof (20) to (35), which further comprises a purification step ofpurifying the hydroxylamine by ion exchange after the concentrationstep.

(37) The process for producing a hydroxylamine as described in (36),wherein the temperature at the purification step after the concentrationstep is from 0 to 70° C.

(38) The process for producing a hydroxylamine as described in any oneof (20) to (37), wherein the salt of hydroxylamine is at least onecompound selected from the group consisting of hydroxylamine sulfate,hydroxylamine hydrochloride, hydroxylamine nitrate and hydroxylaminephosphate.

(39) The process for producing a hydroxylamine as described in any oneof (20) to (38), wherein the alkali compound is at least one compoundselected from the group consisting of an alkali metal compound, analkaline earth metal compound, an ammonia and an amine.

EFFECT OF THE INVENTION

According to the present invention, the yield reduction due to formationof a complex between the produced hydroxylamine and a salt produced as aby-product or adsorption of the hydroxylamine to the by-product salt canbe greatly decreased and a high-concentration and high-purityhydroxylamine can be safely and efficiently produced from a salt ofhydroxylamine at a high yield.

BEST MODE FOR CARRYING OUT THE INVENTION

The production process of a hydroxylamine according to the presentinvention is described in detail below.

Reaction Step

The production process of a hydroxylamine of the present inventioncomprises a reaction step of reacting a salt of hydroxylamine with analkali compound to obtain a hydroxylamine.

The salt of hydroxylamine for use in the present invention includes aninorganic acid salt of hydroxylamine, such as sulfate, hydrochloride,nitrate, phosphate, hydrobromate, sulfite, phosphite, perchlorate,carbonate and hydrogencarbonate, and an organic acid salt ofhydroxylamine, such as formate, acetate and propionate. Among these,preferred is at least one salt selected from the group consisting ofhydroxylamine sulfate (NH₂OH.1/2H₂SO₄), hydroxylamine hydrochloride(NH₂OH.HCl), hydroxylamine nitrate (NH₂OH.HNO₃) and hydroxylaminephosphate (NH₂OH.1/3H₃PO₄).

The salt of hydroxylamine is not particularly limited as long as it iscommercially or industrially available, but those having less metalimpurities are preferred, because if metal impurities are present, theseimpurities sometimes accelerate decomposition of the salt ofhydroxylamine or the produced hydroxylamine. However, impurities havingno effect on the decomposition of the salt of hydroxylamine or thehydroxylamine and being removable at the purification step or the like,or impurities not raising a problem in use of hydroxylamine may becontained.

The salt of hydroxylamine may be used in the form of an intact solid ormay be used after dissolving or suspending it in a solvent. The solventwhich can be used includes water and/or an organic solvent. Examples ofthe organic solvent include a hydrocarbon, an ether and an alcohol, butif the reaction is not affected, the solvent is not limited thereto.Among these solvents, a solvent containing water and/or an alcohol ispreferred. Also, at least a part of the filtrate resulting fromseparation of insoluble salts or the like generated at the reaction maybe used as the solvent.

The amount of the solvent may be appropriately selected according to theconditions such as amount of the salt of hydroxylamine used and reactiontemperature. The amount of the solvent is, in terms of a ratio by massof the solvent to the salt of hydroxylamine (solvent/salt ofhydroxylamine), usually from 0.1 to 1,000, preferably from 1 to 100.

The alkali compound for use in the present invention is preferably atleast one compound selected from the group consisting of an alkalimetal-containing compound, an alkaline earth metal-containing compound,an ammonia and an amine.

Examples of the alkali metal-containing compound include oxides,hydroxides and carbonates of lithium, sodium, potassium, rubidium andcesium. Among these, preferred are hydroxides and carbonates of sodiumand potassium.

Examples of the alkaline earth metal-containing compound include oxides,hydroxides and carbonates of beryllium, magnesium, calcium, strontiumand barium. Among these, preferred are oxides and hydroxides ofmagnesium, calcium, strontium and barium.

The ammonia may be used in the form of a gas or a solution havingdissolved therein ammonia, for example, an aqueous ammonia solution.

As for the amine, a primary amine, a secondary amine and a tertiaryamine can be used. Also, the amine may be a monoamine, a polyaminehaving two or more amino groups within the molecule, such as diamine andtriamine, or a cyclic amine.

Examples of the monoamine include methylamine, dimethylamine,trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine,di-n-propylamine, tri-n-propylamine, i-propylamine, di-i-propylamine,tri-i-propylamine, n-butylamine, di-n-butylamine, tri-n-butylamine,i-butylamine, di-i-butylamine, tri-i-butylamine, sec-butylamine,di-sec-butylamine, tri-sec-butylamine, tert-butylamine,di-tert-butylamine, tri-tert-butylamine, allylamine, diallylamine,triallylamine, cyclohexylamine, dicyclohexylamine, tricyclohexylamine,n-octylamine, di-n-octylamine, tri-n-octylamine, benzylamine,dibenzylamine, tribenzylamine, diaminopropylamine, 2-ethylhexylamine,3-(2-ethylhexyloxy)propylamine, 3-methoxypropylamine,3-ethoxypropylamine, 3-(diethylamino)propylamine,bis(2-ethylhexyl)amine, 3-(dibutylamino)propylamine, α-phenylethylamine,β-phenylethylamine, aniline, N-methylaniline, N,N-dimethylaniline,diphenylamine, triphenylamine, o-toluidine, m-toluidine, p-toluidine,o-anisidine, m-anisidine, p-anisidine, o-chloroaniline, m-chloroaniline,p-chloroaniline, o-bromoaniline, m-bromoaniline, p-bromoaniline,o-nitroaniline, m-nitroaniline, p-nitroaniline, 2,4-dinitroaniline,2,4,6-trinitroaniline, p-aminobenzoic acid, sulfanilic acid,sulfanilamide, monoethanolamine, diethanolamine and triethanolamine.

Examples of the diamine include 1,2-diaminoethane,N,N,N′,N′-tetramethyl-1,2-diaminoethane,N,N,N′,N′-tetra-ethyl-1,2-diaminoethane, 1,3-diaminopropane,N,N,N′,N′-tetramethyl-1,2-diaminopropane,N,N,N′,N′-tetraethyl-1,2-diaminopropane, 1,4-diaminobutane,N-methyl-1,4-diamino-butane, 1,2-diaminobutane,N,N,N′,N′-tetramethyl-1,2-diaminobutane, 3-aminopropyldimethylamine,1,6-diamino-hexane, 3,3-diamino-N-methyldipropylamine,1,2-phenylene-diamine, 1,3-phenylenediamine, 1,4-phenylenediamine andbenzidine.

Examples of the triamine include 2,4,6-triaminophenol,1,2,3-triaminopropane, 1,2,3-triaminobenzene, 1,2,4-triaminobenzene and1,3,5-triaminobenzene.

Examples of the tetramine include β,β′,β″-triamino-triethylamine.

Examples of the cyclic amine include pyrrole, pyridine, pyrimidine,pyrrolidine, piperidine, purine, imidazole, oxazole, thiazole, pyrazole,3-pyrroline, quinoline, isoquinoline, carbazole, piperazine, pyridazine,1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,3-triazole,1,2,5-triazole, 1,2,4-triazole, 1,3,4-triazole and morpholine.

The amine which can be used as the alkali compound for use in thepresent invention is not limited to the compounds described above andmay be, for example, an asymmetric compound differing in the kind ofsubstituent, such as ethylmethylamine. Also, one amine may be used aloneor two or more amines may be used in combination.

The alkali compound for use in the present invention is not particularlylimited as long as it is commercially or industrially available, butsimilarly to the salt of hydroxylamine, those having less metalimpurities are preferred.

The alkali compound can be used after dissolving or suspending it in asolvent. The solvent which can be used here includes water and/or anorganic solvent. Examples of the organic solvent include a hydrocarbon,an ether and an alcohol, but if the reaction is not affected, thesolvent is not limited thereto. Among these solvents, water and/or analcohol are preferred. Also, at least a part of the filtrate resultingfrom separation of insoluble salts or the like generated at the reactionmay be used as the solvent.

The amount of the solvent may be appropriately selected according to theconditions such as amount of the alkali compound used and reactiontemperature. The amount of the solvent is, in terms of a ratio by massof the solvent to the alkali compound (solvent/alkali compound), usuallyfrom 0.5 to 1,000, preferably from 0.8 to 100.

In the production process of a hydroxylamine of the present invention,the reaction step of reacting a salt of hydroxylamine with an alkalicompound to obtain a hydroxylamine may be performed in the presence of astabilizer. The stabilizer may be a known stabilizer. Examples thereofinclude 8-hydroxyquinoline,N-hydroxyethylethylenediamine-N,N,N′-triacetic acid, glycine,ethylenediaminetetraacetic acid,cis-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid,trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid,N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid,N-hydroxyethyliminodiacetic acid, N,N′-dihydroxyethylglycine,diethylenetriaminepentaacetic acid,ethylenebis(oxyethylenenitrilo)tetraacetic acid,bishexamethylenetriaminepentaacetic acid,hexamethylenediaminetetraacetic acid, triethylenetetraminehexaaceticacid, tris(2-aminoethyl)aminehexaacetic acid, iminodiacetic acid,polyethyleneimine, polypropyleneimine, o-aminoquinoline,1,10-phenanthroline, 5-methyl-1,10-phenanthroline,5-chloro-1,10-phenanthroline, 5-phenyl-1,10-phenanthroline,hydroxyanthraquinone, 8-hydroxyquinoline-5-sulfonic acid,8-hydroxymethylquinoline, thioglycolic acid, thiopropionic acid,1-amino-2-mercapto-propionic acid, 2,2-dipyridyl,4,4-dimethyl-2,2-dipyridyl, ammonium thiosulfate, benzotriazole,flavone, morin, quercetin, gossypetin, robinetin, luteolin, fisetin,apigenin, galangin, chrysin, flavonol, pyrogallol, oxyanthraquinone,1,2-dioxyanthraquinone, 1,4-dioxyanthraquinone,1,2,4-trioxyanthraquinone, 1,5-dioxyanthraquinone,1,8-dioxyanthraquinone, 2,3-dioxyanthraquinone,1,2,6-trioxyanthraquinone, 1,2,7-trioxyanthraquinone,1,2,5,8-tetraoxyanthraquinone, 1,2,4,5,8-pentaoxyanthraquinone,1,6,8-dioxy-3-methyl-6-methoxyanthraquinone, quinalizarin, flavan,lactone, 2,3-dihydrohexono-1,4-lactone, 8-hydroxyquinaldine,6-methyl-8-hydroxyquinaldine, 5,8-dihydroxyquinaldine, anthocyan,pelargonidin, cyanidin, delphinidin, paeonidin, petunidin, malvidin,catechin, sodium thiosulfate, nitrilotriacetic acid,2-hydroxyethyldisulfide, 1,4-dimercapto-2,3-butanediol, hydrochloride ofthiamine, catechol, 4-tert-butylcatechol, 2,3-dihydroxynaphthalene,2,3-dihydroxybenzoic acid, 2-hyroxypyridine-N-oxide,1,2-dimethyl-3-hydroxypyridin-4-one, 4-methylpyridine-N-oxide,6-methylpyridine-N-oxide, 1-methyl-3-hydroxypyridin-2-one,2-mercaptobenzothiazole, 2-mercaptocyclohexylthiazole,2-mercapto-6-tert-butylcyclohexylthiazole,2-mercapto-4,5-dimethylthiazoline, 2-mercaptothiazoline,2-mercapto-5-tert-butylthiazoline, tetramethylthiuramdisulfide,tetra-n-butylthiuramdisulfide, N,N′-diethylthiuramdisulfide,tetraphenylthiuramdisulfide, thiuramdisulfide, thiourea,N,N′-diphenylthiourea, di-o-tolylthiourea, ethylenethiourea,thiocetamide, 2-thiouracil, thiocyanuric acid, thioformamide,thioacetamide, thiopropionamide, thiobenzamide, thionicotinamide,thioacetanilide, thiobenzanilide, 1,3-dimethylthiourea,1,3-diethyl-2-thiourea, 1-phenyl-2-thiourea, 1,3-diphenyl-2-thiourea,thiocarbazide, thiosemicarbazide, 4,4-dimethyl-3-thiosemicarbazide,2-mercaptoimidazoline, 2-thiohydantoin, 3-thiourazole, 2-thiouramil,4-thiouramil, thiopentanol, 2-thiobarbituric acid, thiocyanuric acid,2-mercaptoquinoline, 2-mercapto-4H-3,1-benzoxazine,2-mercapto-4H-3,1-benzothiazine, thiosaccharin, 2-mercaptobenzimidazole,trimethylphosphite, triethylphosphite, triphenylphosphite,trimethylphosphine, triethylphosphine and triphenylphosphine.

One of these stabilizers may be used alone or two or more thereof may beused in combination. By adding the stabilizer, the salt of hydroxylamineor the hydroxylamine can be prevented from decomposition due to metalimpurities or the like.

The stabilizer for use in the present invention is not particularlylimited as long as it is commercially or industrially available, butsimilarly to the salt of hydroxylamine, those having less metalimpurities are preferred.

The ratio by mass of the stabilizer to the salt of hydroxylamine(stabilizer/salt of hydroxylamine) is suitably from 1.0×10⁻⁹ to 1.0,preferably from 1.0×10⁻⁸ to 0.1. If this ratio by mass is less than1.0×10⁻⁹, the effect of preventing the salt of hydroxylamine or thehydroxylamine from decomposition reaction due to metal impurities maynot be obtained, whereas if the ratio by mass exceeds 1.0, removal orrecovery of the excess stabilizer may be required.

The stabilizer may be used in the form of an intact solid or may be usedafter dissolving it in a solvent. The solvent which can be used hereincludes water and/or an organic solvent. Examples of the organicsolvent include a hydrocarbon, an ether, an ester and an alcohol, but ifthe reaction is not affected, the solvent is not limited thereto. Amongthese solvents, water and/or an alcohol are preferred. The amount of thesolvent may be appropriately selected according to the conditions suchas kind and amount of the stabilizer used and reaction temperature.

The production process of a hydroxylamine of the present inventioncomprises a reaction step of performing the reaction by adding a salt ofhydroxylamine to a reaction solution prepared by, as described above,dissolving or suspending an alkali compound in a solvent. When such amethod of adding a salt of hydroxylamine to a reaction solutioncontaining an alkali compound is used, the produced hydroxylamine hardlyforms a complex with a salt produced as a by-product and is lessadsorbed to or taken into the by-product insoluble salt.

At the time of adding a salt of hydroxylamine to a reaction solutioncontaining an alkali compound, the salt of hydroxylamine is preferablyadded while keeping the reaction solution at a pH of 7 or more, morepreferably 7.5 or more, still more preferably 8 or more. When thereaction solution is kept at a pH within this range, the producedhydroxylamine hardly forms a complex with a salt produced as aby-product and is less adsorbed to or taken into the by-productinsoluble salt.

In the reaction step of the present invention, it may be also possibleto add an alkali compound to a reaction solution having dissolved orsuspended therein a salt of hydroxylamine.

Furthermore, the reaction step in the production process of ahydroxylamine of the present invention may be a reaction step ofperforming the reaction by simultaneously supplying a salt ofhydroxylamine and an alkali compound. At this time, the amounts added ofthe salt of hydroxylamine and the alkali compound are preferablyadjusted while keeping the reaction solution at a pH of 7 or more, morepreferably 7.5 or more, still more preferably 8 or more. The salt ofhydroxylamine and/or the alkali compound each may be added in the formof an intact solid or may be added after dissolving or suspending it ina solvent. In the case where the alkali compound is ammonia or the like,the alkali compound may also be introduced in the form of a gas.

In the production process of a hydroxylamine of the present invention,the method of adding the stabilizer at the reaction step is notparticularly limited and a known method may be employed. For example,the reaction may be started by previously introducing the stabilizerinto a reactor or the stabilizer may be added as needed on the way ofreaction. Also, the stabilizer may be added by dissolving or suspendingit in a solvent together with the alkali compound and/or the salt ofhydroxylamine.

In this reaction step, the reaction temperature is preferably from 0 to80° C., more preferably from 5 to 50° C. If the reaction temperatureexceeds 80° C., there may arise a problem such as decomposition ofhydroxylamine, whereas if the reaction temperature is less than 0° C.,the reaction rate decreases and this may cause a problem such asreduction in productivity.

The heat of reaction, which is generated accompanying the reactionbetween the salt of hydroxylamine and the alkali compound for use in thepresent invention, can be discharged outside the system by using water,warm water or a heat medium so as to keep the reaction temperature in aconstant range. The heat discharged outside the system by using water,warm water or a heat medium is preferably used as a heat source forother equipment.

In the production process of a hydroxylamine of the present invention,the reaction step may be performed by a known method, for example, batchsystem, semi-batch system or continuous system.

Separation Step

The production process of a hydroxylamine of the present invention maycomprise a step of separating insoluble substances from thehydroxylamine.

The insoluble substance is, for example, an insoluble substanceprecipitated in the reaction solution at the above-described reactionstep.

Examples of the insoluble substance include a salt produced by thereaction between a salt of hydroxylamine and an alkali compound in thereaction step, a salt of hydroxylamine and an alkali compound.

That is, when a salt produced by the reaction between a salt ofhydroxylamine and an alkali compound in the reaction step, a salt ofhydroxylamine, an alkali compound or the like is precipitated as theinsoluble substance resulting from the concentration becoming higherthan the solubility, the production process may comprise a separationstep of separating insoluble substances.

Insoluble substances precipitated in the steps other than the reactionstep can also be separated in the same manner.

As for the separation method, a known method such as filtration,compression, centrifugation, sedimentation and floatation can be used.For example, the separation by filtration may be performed by naturalfiltration, filtration under pressure or filtration under reducedpressure, the separation by sedimentation may be performed bysupernatant separation or precipitation concentration, and theseparation by floatation may be performed by floatation under pressureor floatation using ionization.

Also, by washing the insoluble substance separated in the separationstep of the present invention with a solvent, the hydroxylamine attachedto or taken into the insoluble substance can be recovered.

The solvent used for washing the insoluble substance may be the same asthe solvent used in the reaction step or may be a different solvent. Thewashing solvent which can be used includes water and/or an organicsolvent. Examples of the organic solvent include a hydrocarbon, anether, an ester and an alcohol, but if the recovery of hydroxylamine isnot affected, the solvent is not limited thereto. Among these washingsolvents, water and/or an alcohol are preferred. The amount of thewashing solvent may be appropriately selected according to theconditions such as kind and amount of the insoluble substance andseparation.

The temperature at the time of separating insoluble substances in theseparation step is preferably from 0 to 80° C., more preferably from 5to 50° C. If the temperature at the separation exceeds 80° C., there mayarise a problem such as decomposition of the hydroxylamine, whereas ifthe temperature is less than 0° C., there may arise a problem, forexample, a large energy becomes necessary for cooling.

A part or the whole of the filtrate resulting from separation ofinsoluble substances in the separation step and/or the filtrateresulting from washing of the insoluble substance may also be used as asolvent for dissolving or suspending a salt of hydroxylamine and/or analkali compound which are reaction raw materials.

The separation step is, similarly to the reaction step, preferablyperformed in the presence of a stabilizer for the hydroxylamine. Thestabilizer may be newly added in the separation step or the stabilizeradded in the previous step may be used as it is.

As for the stabilizer, the same stabilizer as that used in the reactionstep or a different stabilizer may be selected according to thecondition or use. By adding a stabilizer, side reaction such asdecomposition of the hydroxylamine due to metal impurities can besuppressed and the production efficiency of hydroxylamine is enhanced.

The amount of the stabilizer used is, in terms of a ratio by mass of thestabilizer to the hydroxylamine (stabilizer/hydroxylamine), suitablyfrom 1.0×10⁻⁹ to 1.0, preferably from 1.0×10⁻⁸ to 0.1. If this ratio bymass is less than 1.0×10⁻⁹, the effect of preventing the hydroxylaminefrom decomposition reaction due to metal impurities may not be obtained,whereas if the ratio by mass exceeds 1.0, removal or recovery of theexcess stabilizer may be required.

In the production process of a hydroxylamine of the present invention,the separation step may be performed by a known method, for example,batch system, semi-batch system or continuous system.

Purification Step

The production process of a hydroxylamine of the present invention maycomprise a step of purifying the hydroxylamine obtained as above.

For the purification, a known method such as distillation, ion exchange,electrodialysis, membrane separation, adsorption and crystallization canbe used.

The distillation can be performed by a known method such as simpledistillation, multistage distillation, steam distillation and flashdistillation. By distilling the hydroxylamine-containing reactionsolution with use of such a known method, a purified hydroxylamine canbe obtained from the top, side or bottom of a distillation column.

For example, by simple or multistage distillation under reducedpressure, a purified hydroxylamine can be obtained from the top of adistillation column. Furthermore, by introducing steam into thedistillation column and performing stripping, a purified hydroxylaminecan also be obtained from the top of the distillation column. Inaddition, the purification can also be performed by concentrating thehydroxylamine-containing reaction solution in the column, taking out thehydroxylamine-containing vapor from the side at the column bottom andconcentrating the vapor.

The ion exchange may be performed by a known method such as cationexchange, anion exchange and chelate exchange.

The purification by cation exchange can be performed by a known methodusing a strongly acidic cation exchange resin, a weakly acidic cationexchange resin or the like. The cation exchange resin is preferably usedin the form of H type by previously subjecting it to an acid treatment.

The purification by anion exchange can be performed by a known methodusing a strongly basic anion exchange resin, a weakly basic anionexchange resin or the like. The anion exchange resin is preferably usedin the form of OH type by previously subjecting it to an alkalitreatment.

The purification by chelate exchange can be performed by a known methodusing a chelate exchange resin or the like. The chelate exchange resinis preferably used in the form of H type by previously subjecting it toan acid treatment.

The purification may also be performed by combining cation exchange,anion exchange and chelate exchange. For example, anion exchange may beperformed after cation exchange, or cation exchange may be performedafter anion exchange. Also, monobed resin or mixed bed resin obtained bymixing cation exchange resin and anion exchange resin may be used.

The temperature at the ion exchange is preferably from 0 to 70° C., morepreferably from 5 to 50° C. If the ion exchange temperature exceeds 70°C., there may arise a problem such as decomposition of thehydroxylamine, whereas if the ion exchange temperature is less than 0°C., there may arise a problem, for example, a large energy becomesnecessary for cooling.

The electrodialysis can be performed by a known method using a cationselective membrane, an anion selective membrane, a bipolar membrane orthe like.

For example, in a two-compartment electrodialyzer comprising atwo-compartment unit formed by alternately disposing an anion selectivemembrane and a cation selective membrane, where one compartment is usedas a desalting compartment and the other compartment adjacent thereto isused as a concentration compartment, an aqueous hydroxylamine solutionis supplied to the desalting compartment and by applying a current, thehydroxylamine can be purified.

The membrane separation can be performed by a known method using asemipermeable membrane or the like. For example, by passing an aqueoushydroxylamine solution through a semipermeable membrane, thehydroxylamine can be purified.

The adsorption and crystallization each can be performed by a knownmethod.

A part of the hydroxylamine solution obtained in the purification stepmay be used as a solvent for dissolving or suspending a salt ofhydroxylamine and/or an alkali compound which are reaction rawmaterials.

The purification step is, similarly to the reaction step, preferablyperformed in the presence of a stabilizer for the hydroxylamine. Thestabilizer may be newly added in the purification step or the stabilizeradded in the previous step may be used as it is.

As for the stabilizer, the same stabilizer as that used in the reactionstep or a different stabilizer may be selected according to thecondition or use. By adding a stabilizer, side reaction such asdecomposition of the hydroxylamine due to metal impurities can besuppressed and the production efficiency of hydroxylamine is enhanced.

The amount of the stabilizer used is, in terms of a ratio by mass of thestabilizer to the hydroxylamine (stabilizer/hydroxylamine), suitablyfrom 1.0×10⁻⁹ to 1.0, preferably from 1.0×10⁻⁸ to 0.1. If this ratio bymass is less than 1.0×10⁻⁹, the effect of preventing the hydroxylaminefrom decomposition reaction due to metal impurities may not be obtained,whereas if the ratio by mass exceeds 1.0, removal or recovery of theexcess stabilizer may be required.

In the production process of a hydroxylamine of the present invention,the purification step by ion exchange may be performed by a knownmethod, for example, batch system, semi-batch system or continuoussystem.

Concentration Step

The production process of a hydroxylamine of the present invention maycomprise a step of concentrating the hydroxylamine.

The concentration can be performed by a known method such asdistillation, electrodialysis and membrane separation. In the productionprocess of the present invention, the method in the purification stepand the method in the concentration step may be the same or different.Also, purification and concentration may be performed at the same time.Preferably, the production process of the present invention comprises astep of concentrating the hydroxylamine by distillation at the columnbottom.

The distillation can be performed by a known method such as simpledistillation, multistage distillation, steam distillation and flashdistillation.

For example, by simple distillation or multistage distillation, anaqueous solution containing a slight amount of hydroxylamine isdistilled out from the column top and a hydroxylamine solution having ahigh hydroxylamine concentration can be obtained from the column bottom.

The distillation column may be a general plate column such as bubble captray column or sieve plate column or may be equipped with a generalpacking material such as Raschig ring, pearl ring and saddle body.

The distillation temperature is, in terms of temperature at the columnbottom, preferably from 0 to 70° C., more preferably from 5 to 60° C. Ifthe temperature at the column bottom exceeds 70° C., there may arise aproblem such as decomposition of hydroxylamine, whereas if thetemperature at the column bottom is less than 0° C., there may arise aproblem, for example, a large energy becomes necessary for cooling.

The distillation pressure is determined according to the relationshipwith the temperature but this is, in terms of pressure at the columnbottom, preferably from 0.5 to 60 kPa, more preferably from 0.8 to 40kPa.

A part of the hydroxylamine solution obtained in the concentration stepmay be used as a solvent for dissolving or suspending a salt ofhydroxylamine and/or an alkali compound which are reaction rawmaterials.

In some cases, a low-concentration hydroxylamine solution is obtainedfrom the top or side of the distillation column, but a part or the wholethereof may be used as a solvent for dissolving or suspending a salt ofhydroxylamine and/or an alkali compound which are reaction rawmaterials.

For example, by using distillation, an aqueous solution containing aslight amount of hydroxylamine is distilled out from the column top andan aqueous hydroxylamine solution having a high hydroxylamineconcentration can be obtained from the column bottom. Depending on thedistillation conditions, it is also possible to obtain an aqueoushydroxylamine solution having a high hydroxylamine concentration fromthe column top.

Depending on the distillation conditions, it is also possible to obtainan aqueous hydroxylamine solution having a high hydroxylamineconcentration from the column top.

The concentration step is, similarly to the reaction step, preferablyperformed in the presence of a stabilizer for the hydroxylamine. Thestabilizer may be newly added in the concentration step or thestabilizer added in the previous step may be used as it is.

As for the stabilizer, the same stabilizer as that used in the reactionstep or a different stabilizer may be selected according to thecondition or use. By adding a stabilizer, side reaction such asdecomposition of the hydroxylamine due to metal impurities can besuppressed and the production efficiency of hydroxylamine is enhanced.

The amount of the stabilizer used is, in terms of a ratio by mass of thestabilizer to the hydroxylamine (stabilizer/hydroxylamine), suitablyfrom 1.0×10⁻⁹ to 1.0, preferably from 1.0×10⁻⁸ to 0.1. If this ratio bymass is less than 1.0×10⁻⁹, the effect of preventing the hydroxylaminefrom decomposition reaction due to metal impurities may not be obtained,whereas if the ratio by mass exceeds 1.0, removal or recovery of theexcess stabilizer may be required.

In the production process of a hydroxylamine of the present invention,the concentration step may be performed by a known method, for example,batch system, semi-batch system or continuous system.

The production process of a hydroxylamine of the present invention maycomprise a purification step of purifying by ion exchange thehydroxylamine obtained in the concentration step.

The ion exchange may be performed by a known method such as cationexchange, anion exchange and chelate exchange.

The purification by cation exchange can be performed by a known methodusing a strongly acidic cation exchange resin, a weakly acidic cationexchange resin or the like. The cation exchange resin is preferably usedin the form of H type by previously subjecting it to an acid treatment.

The purification by anion exchange can be performed by a known methodusing a strongly basic anion exchange resin, a weakly basic anionexchange resin or the like. The anion exchange resin is preferably usedin the form of OH type by previously subjecting it to an alkalitreatment.

The purification by chelate exchange can be performed by a known methodusing a chelate exchange resin or the like. The chelate exchange resinis preferably used in the form of H type by previously subjecting it toan acid treatment.

The purification may also be performed by combining cation exchange,anion exchange and chelate exchange. For example, anion exchange may beperformed after cation exchange or cation exchange may be performedafter anion exchange. Also, monobed resin or mixed bed resin obtained bymixing cation exchange resin and anion exchange resin may be used.

The temperature at the ion exchange is preferably from 0 to 70° C., morepreferably from 5 to 50° C. If the ion exchange temperature exceeds 70°C., there may arise a problem such as decomposition of thehydroxylamine, whereas if the ion exchange temperature is less than 0°C., there may arise a problem, for example, a large energy becomesnecessary for cooling.

A part of the hydroxylamine solution obtained in the purification stepmay be used as a solvent for dissolving or suspending a salt ofhydroxylamine and/or an alkali compound which are reaction rawmaterials.

This purification step is, similarly to the reaction step, preferablyperformed in the presence of a stabilizer for the hydroxylamine. Thestabilizer may be newly added in the purification step or the stabilizeradded in the previous step may be used as it is.

As for the stabilizer, the same stabilizer as that used in the reactionstep or a different stabilizer may be selected according to thecondition or use. By adding a stabilizer, side reaction such asdecomposition of the hydroxylamine due to metal impurities can besuppressed and the production efficiency of hydroxylamine is enhanced.

The amount of the stabilizer used is, in terms of a ratio by mass of thestabilizer to the hydroxylamine (stabilizer/hydroxylamine), suitablyfrom 1.0×10⁻⁹ to 1.0, preferably from 1.0×10⁻⁸ to 0.1. If this ratio bymass is less than 1.0×10⁻⁹, the effect of preventing the hydroxylaminefrom decomposition reaction due to metal impurities may not be obtained,whereas if the ratio by mass exceeds 1.0, removal or recovery of theexcess stabilizer may be required.

The production process of a hydroxylamine of the present inventioncomprises:

(1) a reaction step of reacting a salt of hydroxylamine with an alkalicompound to obtain a hydroxylamine,

(2) a purification step of purifying the hydroxylamine by ion exchange,and

(3) a concentration step of concentrating the hydroxylamine bydistillation at the column bottom, and these steps are preferablyperformed in the order of reaction step, purification step andconcentration step. Also, the steps (1) to (3) may be performed in anyorder after the step (1) is performed, or the same step may be performedtwo or more times.

The production process of a hydroxylamine of the present invention maycomprise (4) a separation step of separating insoluble substances fromthe hydroxylamine. This step is preferably performed between thereaction step and the purification step.

The concentration of hydroxylamine obtained by the process of thepresent invention is 10 mass % or more. Also, a hydroxylamine in aconcentration of 20 mass % or more can be obtained, and even ahydroxylamine in a concentration of 40 mass % or more can be obtained.

In the hydroxylamine obtained by the process of the present invention,the content of each metal contained as an impurity is 1 ppm by mass orless. Also, a hydroxylamine where the content of each metal is 0.1 ppmby mass or less can be obtained, and even a hydroxylamine where thecontent of each metal is 0.01 ppm by mass or less can be obtained. Themetal includes an alkali metal and an alkaline earth metal, which areoriginated in the alkali compound used in the reaction step, and alsoincludes Fe or the like which outstandingly accelerates thedecomposition of hydroxylamine.

In the hydroxylamine obtained by the process of the present invention,the content of each anion contained as an impurity is 100 ppm by mass orless. Also, a hydroxylamine where the content of each anion is 10 ppm bymass or less can be obtained, and even a hydroxylamine where the contentof each anion is 1 ppm by mass or less can be obtained. The anionincludes sulfate ion, chloride ion, nitrate ion and the like, which areoriginated in the salt of hydroxylamine used as a raw material.

In the hydroxylamine finally obtained by the present invention, astabilizer may be newly added or the stabilizer added in the previousstep may be used as it is. As for the stabilizer, the same stabilizer asthat used in the reaction step or a different stabilizer may be selectedaccording to the condition or use. By adding a stabilizer, side reactionsuch as decomposition of the hydroxylamine due to metal impurities canbe suppressed and the production efficiency of hydroxylamine isenhanced.

EXAMPLES

The present invention is described in greater detail below by referringto Examples, but the present invention is not limited to these Examples.

Example 1

In a 1 L-volume glass-made reactor, 61.7 g (1.1 mol) of CaO, 1.45 g(0.01 mol) of 8-hydroxyquinoline and 332 g (18.4 mol) of H₂O werecharged and stirred at 20° C. At this time, the pH of the reactionsolution was 12.8. To this reaction solution under stirring, a solutionobtained by dissolving 164 g (2.0 mol) of hydroxylamine sulfate in 246 g(13.7 mol) of H₂O was added while keeping the reaction solution at a pHof 7 or more. The time required for the addition was about 40 minutes.After the addition, the reaction was further allowed to proceed at 20°C. for 3 hours. The final pH of the reaction solution was 12.2.

After the completion of reaction, the reaction solution at 20° C. wasfiltered under reduced pressure to separate an insoluble solid from thereaction solution and the obtained solid was washed 5 times with 66.1 g(3.67 mol) of H₂O at 20° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was7.4 mass %. Accordingly, the amount of hydroxylamine obtained was 64.7 g(1.96 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 98%.

Example 2

The reaction was performed in the same manner as in Example 1 except forperforming the reaction at 40° C. The final pH of the reaction solutionwas 12.2. After the completion of reaction, the reaction solution at 40°C. was filtered under reduced pressure to separate an insoluble solidfrom the reaction solution and the obtained solid was washed 5 timeswith 66.1 g (3.67 mol) of H₂O at 40° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was7.4 mass %. Accordingly, the amount of hydroxylamine obtained was 63.8 g(1.93 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 97%.

Example 3

The reaction was performed in the same manner as in Example 1 except forperforming the reaction at 10° C. The final pH of the reaction solutionwas 12.2. After the completion of reaction, the reaction solution at 10°C. was filtered under reduced pressure to separate an insoluble solidfrom the reaction solution and the obtained solid was washed 5 timeswith 66.1 g (3.67 mol) of H₂O at 10° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was7.3 mass %. Accordingly, the amount of hydroxylamine obtained was 63.0 g(1.91 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 96%.

Example 4

In a 1 L-volume glass-made reactor, 61.7 g (1.1 mol) of CaO, 1.45 g(0.01 mol) of 8-hydroxyquinoline and 578 g (32.1 mol) of H₂O werecharged and stirred at 20° C. At this time, the pH of the reactionsolution was 12.9. To this reaction solution under stirring, 164 g (2.0mol) of hydroxylamine sulfate was added in the form of an intact solidwhile keeping the reaction solution at a pH of 7 or more. The timerequired for the addition was about 40 minutes. After the addition, thereaction was further allowed to proceed at 20° C. for 3 hours. The finalpH of the reaction solution was 12.2.

After the completion of reaction, the reaction solution at 20° C. wasfiltered under reduced pressure to separate an insoluble solid from thereaction solution and the obtained solid was washed 5 times with 66.1 g(3.67 mol) of H₂O at 20° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was7.5 mass %. Accordingly, the amount of hydroxylamine obtained was 64.7 g(1.96 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 98%.

Example 5

The reaction was performed in the same manner as in Example 4 except forperforming the reaction at 40° C. The final pH of the reaction solutionwas 12.2. After the completion of reaction, the reaction solution at 40°C. was filtered under reduced pressure to separate an insoluble solidfrom the reaction solution and the obtained solid was washed 5 timeswith 66.1 g (3.67 mol) of H₂O at 40° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was7.4 mass %. Accordingly, the amount of hydroxylamine obtained was 64.1 g(1.94 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 97%.

Example 6

The reaction was performed in the same manner as in Example 4 except forperforming the reaction at 10° C. The final pH of the reaction solutionwas 12.3. After the completion of reaction, the reaction solution at 10°C. was filtered under reduced pressure to separate an insoluble solidfrom the reaction solution and the obtained solid was washed 5 timeswith 66.1 g (3.67 mol) of H₂O at 10° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was7.4 mass %. Accordingly, the amount of hydroxylamine obtained was 63.4 g(1.92 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 96%.

Example 7

In a 1 L-volume glass-made reactor, 61.7 g (1.1 mol) of CaO, 1.45 g(0.01 mol) of 8-hydroxyquinoline and 248 g (13.8 mol) of H₂O werecharged and stirred at 20° C. At this time, the pH of the reactionsolution was 13.0. To this reaction solution under stirring, 164 g (2.0mol) of hydroxylamine sulfate was added in the form of an intact solidwhile keeping the reaction solution at a pH of 7 or more. The timerequired for the addition was about 40 minutes. After the addition, thereaction was further allowed to proceed at 20° C. for 3 hours. The finalpH of the reaction solution was 12.3.

After the completion of reaction, the reaction solution at 20° C. wasfiltered under reduced pressure to separate an insoluble solid from thereaction solution and the obtained solid was washed 5 times with 66.1 g(3.67 mol) of H₂O at 20° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was11.8 mass %. Accordingly, the amount of hydroxylamine obtained was 62.8g (1.90 mol) and the yield of hydroxylamine based on hydroxylaminesulfate was 95%.

Example 8

The reaction was performed in the same manner as in Example 7 except forperforming the reaction at 40° C. The final pH of the reaction solutionwas 12.3. After the completion of reaction, the reaction solution at 40°C. was filtered under reduced pressure to separate an insoluble solidfrom the reaction solution and the obtained solid was washed 5 timeswith 66.1 g (3.67 mol) of H₂O at 40° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was11.6 mass %. Accordingly, the amount of hydroxylamine obtained was 62.1g (1.88 mol) and the yield of hydroxylamine based on hydroxylaminesulfate was 94%.

Example 9

The reaction was performed in the same manner as in Example 7 except forperforming the reaction at 10° C. The final pH of the reaction solutionwas 12.3. After the completion of reaction, the reaction solution at 10°C. was filtered under reduced pressure to separate an insoluble solidfrom the reaction solution and the obtained solid was washed 5 timeswith 66.1 g (3.67 mol) of H₂O at 10° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was11.6 mass %. Accordingly, the amount of hydroxylamine obtained was 61.5g (1.86 mol) and the yield of hydroxylamine based on hydroxylaminesulfate was 93%.

Example 10

An Na-type strongly acidic cation exchange resin (Amberlite IR120B,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into H type by passing anaqueous 1N—HCl solution, and then thoroughly washed with H₂O. Throughthis strongly acidic cation exchange resin, an aqueous solution ofhydroxylamine obtained in the same manner as in Example 1 was passed ata space velocity (SV) of 1/h. The resulting aqueous solution wasanalyzed by ICP-MS (Model SPQ-900, manufactured by Seiko InstrumentsInc.), as a result, each concentration of impurities Na, Ca and Fe was10 ppb by mass or less.

Example 11

The same procedure as in Example 10 was performed except for using anaqueous 1N—H₂SO₄ solution in place of the aqueous 1N—HCl solution. Thesame results were obtained.

Example 12

A Cl-type strongly basic anion exchange resin (Amberlite IRA900J,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into OH type by passingan aqueous 1N—NaOH solution, and then thoroughly washed with H₂O.Through this strongly basic anion exchange resin, an aqueous solution ofhydroxylamine obtained and deprived of impurity metal ion in the samemanner as in Example 10 was passed at a space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 7mass %. Also, this aqueous solution was analyzed by anion chromatography(SHODEX IC SI-90 4E, produced by Showa Denko K.K.), as a result, eachconcentration of impurities sulfate ion and chloride ion was 1.0 ppm bymass or less.

Example 13

An aqueous solution of hydroxylamine obtained in the same manner as inExample 12 was further concentrated by distillation under reducedpressure. The degree of pressure reduction was adjusted to give a columnbottom temperature of 30° C. or less. Water was extracted from thecolumn top and an aqueous solution having a high hydroxylamineconcentration was recovered from the column bottom.

The bottom solution obtained was analyzed by titration with hydrochloricacid, as a result, the hydroxylamine concentration was 51 mass %.

Example 14

An Na-type strongly acidic cation exchange resin (Amberlite IR120B,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into H type by passing anaqueous 1N—HCl solution, and then thoroughly washed with H₂O. Throughthis strongly acidic cation exchange resin, an aqueous solution ofhydroxylamine obtained in the same manner as in Example 13 was passed ata space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 51mass %. Also, this aqueous solution was analyzed by ICP-MS (ModelSPQ-900, manufactured by Seiko Instruments Inc.), as a result, eachconcentration of impurities Na, Ca and Fe was 10 ppb by mass or less.

Example 15

A Cl-type strongly basic anion exchange resin (Amberlite IRA900J,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into OH type by passingan aqueous 1N—NaOH solution, and then thoroughly washed with H₂O.Through this strongly basic anion exchange resin, an aqueous solution ofhydroxylamine obtained and deprived of impurity metal ion in the samemanner as in Example 14 was passed at a space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 51mass %. Also, this aqueous solution was analyzed by anion chromatography(SHODEX IC SI-90 4E, produced by Showa Denko K.K.), as a result, eachconcentration of impurities sulfate ion and chloride ion was 1.0 ppm bymass or less.

Example 16

A monobed resin (Amberlite ESG-1, ultrapure water grade, produced byJapan Organo Co., Ltd.) was packed into a polytetrafluoroethylene-madecolumn and thoroughly washed with H₂O. Through this monobed resin, anaqueous solution of hydroxylamine obtained in the same manner as inExample 13 was passed at a space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 51mass %. Also, this aqueous solution was analyzed by ICP-MS (ModelSPQ-900, manufactured by Seiko Instruments Inc.), as a result, eachconcentration of impurities sulfate ion and chloride ion was 1.0 ppm bymass or less.

Example 17

In a 2 L-volume glass-made reactor, 61.7 g (1.10 mol) of CaO, 0.041 g(0.28 mmol) of 8-hydroxyquinoline and 350 g (19.4 mol) of H₂O werecharged and stirred at 20° C. At this time, the pH of the reactionsolution was 12.8. To this reaction solution under stirring, 164 g (2.0mol) of hydroxylamine sulfate in 465 g (25.8 mol) of H₂O was added whilekeeping the reaction solution at a pH of 7 or more. The time requiredfor the addition was about 40 minutes. After the addition, the reactionwas further allowed to proceed at 20° C. for 3 hours. The final pH ofthe reaction solution was 12.2.

After the completion of reaction, the reaction solution at 20° C. wasfiltered under reduced pressure to separate an insoluble solid from thereaction solution and the obtained solid was washed 5 times with 66.1 g(3.67 mol) of H₂O at 20° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was4.8 mass %. Accordingly, the amount of hydroxylamine obtained was 64.7 g(1.96 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 98%.

Example 18

In a 1 L-volume glass-made reactor, 220 g of an aqueous 20 mass % NaOHsolution (NaOH: 1.1 mol) and 0.73 g (0.005 mol) of 8-hydroxyquinolinewere charged and stirred at 20° C. While stirring this reactionsolution, a solution obtained by dissolving 82.1 g (1.0 mol) ofhydroxylamine sulfate in 465 g (25.8 mol) of H₂O was added over about 40minutes. After the addition, the reaction was further allowed to proceedat 20° C. for 3 hours.

The reaction solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration was 4.2 mass %.Accordingly, the amount of hydroxylamine obtained was 32.4 g (0.98 mol)and the yield of hydroxylamine based on hydroxylamine sulfate was 98%.

Example 19

An Na-type strongly acidic cation exchange resin (Amberlite IR120B,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into H type by passing anaqueous 1N—HCl solution, and then thoroughly washed with H₂O. Throughthis strongly acidic cation exchange resin, an aqueous solution ofhydroxylamine obtained in the same manner as in Example 18 was passed ata space velocity (SV) of 1/h. The resulting aqueous solution wasanalyzed by ICP-MS (Model SPQ-900, manufactured by Seiko InstrumentsInc.), as a result, each concentration of impurities Na, Ca and Fe was10 ppb by mass or less.

Example 20

The same procedure as in Example 19 was performed except for using anaqueous 1N—H₂SO₄ solution in place of the aqueous 1N—HCl solution. Thesame results were obtained.

Example 21

A Cl-type strongly basic anion exchange resin (Amberlite IRA900J,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into OH type by passingan aqueous 1N—NaOH solution, and then thoroughly washed with H₂O.Through this strongly basic anion exchange resin, an aqueous solution ofhydroxylamine obtained and deprived of impurity metal ion in the samemanner as in Example 19 was passed at a space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 4.0mass %. Also, this aqueous solution was analyzed by anion chromatography(SHODEX IC SI-90 4E, produced by Showa Denko K.K.), as a result, eachconcentration of impurities sulfate ion and chloride ion was 1.0 ppm bymass or less.

Example 22

An aqueous solution of hydroxylamine obtained in the same manner as inExample 21 was further concentrated by distillation under reducedpressure. The degree of pressure reduction was adjusted to give a bottomtemperature of 30° C. or less. Water was extracted from the column topand an aqueous solution having a high hydroxylamine concentration wasrecovered from the column bottom.

The bottom solution obtained was analyzed by titration with hydrochloricacid, as a result, the hydroxylamine concentration was 51 mass %.

Example 23

An Na-type strongly acidic cation exchange resin (Amberlite IR120B,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into H type by passing anaqueous 1N—HCl solution, and then thoroughly washed with H₂O. Throughthis strongly acidic cation exchange resin, an aqueous solution ofhydroxylamine obtained in the same manner as in Example 22 was passed ata space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 51mass %. Also, this aqueous solution was analyzed by ICP-MS (ModelSPQ-900, manufactured by Seiko Instruments Inc.), as a result, eachconcentration of impurities Na, Ca and Fe was 10 ppb by mass or less.

Example 24

A Cl-type strongly basic anion exchange resin (Amberlite IRA900J,produced by Japan Organo Co., Ltd.) was packed into apolytetrafluoroethylene-made column, converted into OH type by passingan aqueous 1N—NaOH solution, and then thoroughly washed with H₂O.Through this strongly basic anion exchange resin, an aqueous solution ofhydroxylamine obtained and deprived of impurity metal ion in the samemanner as in Example 23 was passed at a space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 51mass %. Also, this aqueous solution was analyzed by anion chromatography(SHODEX IC SI-90 4E, produced by Showa Denko K.K.), as a result, eachconcentration of impurities sulfate ion and chloride ion was 1.0 ppm bymass or less.

Example 25

A monobed resin (Amberlite ESG-1, ultrapure water grade, produced byJapan Organo Co., Ltd.) was packed into a polytetrafluoroethylene-madecolumn and thoroughly washed with H₂O. Through this monobed resin, anaqueous solution of hydroxylamine obtained in the same manner as inExample 22 was passed at a space velocity (SV) of 1/h.

The resulting aqueous solution was analyzed by titration withhydrochloric acid, as a result, the hydroxylamine concentration was 51mass %. Also, this aqueous solution was analyzed by ICP-MS (ModelSPQ-900, manufactured by Seiko Instruments Inc.), as a result, eachconcentration of impurities sulfate ion and chloride ion was 1.0 ppm bymass or less.

Comparative Example 1

In a 1 L-volume glass-made reactor, 164 g (2.0 mol) of hydroxylaminesulfate and 246 g (13.7 mol) of H₂O were charged and stirred at 20° C.At this time, the pH of the reaction solution was 3.3. While stirringthis reaction solution, 61.7 g (1.1 mol) of CaO, 1.45 g (0.01 mol) of8-quinolinol and 332 g (18.4 mol) of H₂O were added. The time requiredfor the addition was about 40 minutes. The pH immediately after thecompletion of addition was 3.8. After the addition, the reaction wasfurther allowed to proceed at 20° C. for 3 hours. The final pH of thereaction solution was 12.2.

After the completion of reaction, the reaction solution at 20° C. wasfiltered by suction to separate an insoluble solid from the reactionsolution and the obtained solid was washed 5 times with 66.1 g (3.67mol) of H₂O at 20° C.

The reaction solution after separation of the insoluble solid and thesolution resulting from washing of the solid separated were mixed andthe obtained solution was analyzed by titration with hydrochloric acid.As a result, the hydroxylamine concentration in the mixed solution was3.9 mass %. Accordingly, the amount of hydroxylamine obtained was 33.0 g(1.0 mol) and the yield of hydroxylamine based on hydroxylamine sulfatewas 50%.

1. A process for producing a hydroxylamine by reacting a salt ofhydroxylamine with an alkali compound, comprising a reaction step ofreacting a salt of hydroxylamine with an alkali compound while keepingthe reaction solution at a ph of 7 or more, a concentration step ofconcentrating the hydroxylamine, and a purification step of purifyingthe hydroxylamine by ion exchange after said concentration step.
 2. Aprocess for producing a hydroxylamine by reacting a salt ofhydroxylamine with an alkali compound, comprising a reaction step ofperforming the reaction by adding a salt of hydroxylamine to a reactionsolution containing an alkali compound, wherein said reaction step isperformed while keeping the reaction solution at a ph of 7 or more. 3.The process for producing a hydroxylamine as claimed in claims 1 or 2,wherein said alkali compound is at least one compound selected from thegroup consisting of an alkali metal compound, an alkaline earth metalcompound, an ammonia and an amine.
 4. The process for producing ahydroxylamine as claimed in claims 1 or 2, wherein said salt ofhydroxylamine is at least one salt selected from the group consisting ofhydroxylamine sulfate, hydroxylamine hydrochloride, hydroxylaminenitrate and hydroxylamine phosphate.
 5. The process for producing ahydroxylamine as claimed in claims 1 or 2, wherein the reactiontemperature at said reaction step is from 0 to 80° C.
 6. The process forproducing a hydroxylamine as claimed in claims 1 or 2, wherein saidreaction step is performed in the presence of a solvent containing waterand/or an alcohol.
 7. The process for producing a hydroxylamine asclaimed in claims 1 or 2, wherein said reaction step is performed in thepresence of a stabilizer.
 8. The process for producing a hydroxylamineas claimed in claims 1 or 2, which comprises a separation step ofseparating insoluble substances from the hydroxylamine.
 9. The processfor producing a hydroxylamine as claimed in claim 8, wherein thetemperature at said separation step is from 0 to 80° C.
 10. The processfor producing a hydroxylamine as claimed in claim 8, wherein at least apart of the reaction solution after separating insoluble substances insaid separation step is used as a solvent for dissolving or suspending asalt of hydroxylamine and/or an alkali compound which are reaction rawmaterials.
 11. The process for producing a hydroxylamine as claimed inclaims 1 or 2, which comprises a purification step of purifying thehydroxylamine.
 12. The process for producing a hydroxylamine as claimedin claim 11, wherein said purification step is a step of purifying thehydroxylamine by at least one method selected from the group consistingof distillation, ion exchange, electrodialysis, membrane separation,adsorption and crystallization.
 13. The process for producing ahydroxylamine as claimed in claim 11, wherein at least a part of thehydroxylamine solution obtained in said purification step is used as asolvent for dissolving or suspending a salt of hydroxylamine and/or analkali compound which are reaction raw materials.
 14. The process forproducing a hydroxylamine as claimed in claim 1 wherein saidconcentration step is a step of concentrating the hydroxylamine bydistillation at the column bottom.
 15. The process for producing ahydroxylamine as claimed in claim 1, wherein the temperature at saidconcentration step is from 0 to 70° C.
 16. The process for producing ahydroxylamine as claimed in claim 1, wherein at least a part of thehydroxylamine solution obtained in said concentration step is used as asolvent for dissolving or suspending a salt of hydroxylamine and/or analkali compound which are reaction raw materials.
 17. A process forproducing a hydroxylamine, comprising a reaction step of reacting a saltof hydroxylamine with an alkali compound to obtain a hydroxylamine, apurification step of purifying the hydroxylamine by ion exchange, and aconcentration step of concentrating the hydroxylamine by distillation atthe column bottom.
 18. The process for producing a hydroxylamine asclaimed in claim 17, wherein said steps for producing a hydroxylamineare performed in the order of a reaction step, a purification step and aconcentration step.
 19. The process for producing a hydroxylamine asclaimed in claim 17, wherein each of said steps is performed in thepresence of a stabilizer.
 20. The process for producing a hydroxylamineas claimed in claim 17, which comprises a separation step of separatinginsoluble substances from the hydroxylamine.
 21. The process forproducing a hydroxylamine as claimed in claim 20, wherein thetemperature at said separation step is from 0 to 80° C.
 22. The processfor producing a hydroxylamine as claimed in claim 20, wherein said stepsfor producing a hydroxylamine are performed in the order of a reactionstep, a separation step, a purification step and a concentration step.23. The process for producing a hydroxylamine as claimed in claim 20,wherein each of said steps is performed in the presence of a stabilizer.24. The process for producing a hydroxylamine as claimed in claim 20,wherein at least a part of the reaction solution after separatinginsoluble substances in said separation step is used as a solvent fordissolving or suspending a salt of hydroxylamine and/or an alkalicompound which are reaction raw materials.
 25. The process for producinga hydroxylamine as claimed in claim 17, wherein said reaction step isperformed while keeping the reaction solution at a pH of 7 or more. 26.The process for producing a hydroxylamine as claimed in claim 25,wherein said reaction step is a step of adding a salt of hydroxylamineto a reaction solution containing an alkali compound.
 27. The processfor producing a hydroxylamine as claimed in claim 17, wherein thereaction temperature at said reaction step is from 0 to 80° C.
 28. Theprocess for producing a hydroxylamine as claimed in claim 17, whereinsaid reaction step is performed in the presence of a solvent containingwater and/or an alcohol.
 29. The process for producing a hydroxylamineas claimed in claim 17, wherein the temperature at said purificationstep is from 0 to 70° C.
 30. The process for producing a hydroxylamineas claimed in claim 17, wherein at least a part of the hydroxylaminesolution obtained in said purification step is used as a solvent fordissolving or suspending a salt of hydroxylamine and/or an alkalicompound which are reaction raw materials.
 31. The process for producinga hydroxylamine as claimed in claim 17, wherein the temperature at saidconcentration step is from 0 to 70° C.
 32. The process for producing ahydroxylamine as claimed in claim 17, wherein at least a part of thehydroxylamine solution obtained in said concentration step is used as asolvent for dissolving or suspending a salt of hydroxylamine and/or analkali compound which are reaction raw materials.
 33. The process forproducing a hydroxylamine as claimed in claim 17, which furthercomprises a purification step of purifying the hydroxylamine by ionexchange after said concentration step.
 34. The process for producing ahydroxylamine as claimed in claim 33, wherein the temperature at saidpurification step after the concentration step is from 0 to 70° C. 35.The process for producing a hydroxylamine as claimed in claim 17,wherein said salt of hydroxylamine is at least one compound selectedfrom the group consisting of hydroxylamine sulfate, hydroxylaminehydrochloride, hydroxylamine nitrate and hydroxylamine phosphate. 36.The process for producing a hydroxylamine as claimed in claim 17,wherein said alkali compound is at least one compound selected from thegroup consisting of an alkali metal compound, an alkaline earth metalcompound, an ammonia and an amine.